The purpose of the Biomarker Core facility is to provide a comprehensive, centralized resource for biomarker analyses required for the evaluation of cartilage matrix metabolism and the role of inflammation in the pathogenesis of OA. This Core will serve all of the projects of the Program Project proposal which are linked by a common interest in the role of biomechanical factors and inflammation in modifying joint tissue metabolism and their contribution to osteoarthritis. The expertise offered through this core facility will permit molecular analyses of factors associated with cartilage matrix metabolism and inflammation from both animal and human samples including serum, synovial fluid, and urine. The Core offers the capability of measuring multiple analytes from small sample volumes with high sensitivity, which is especially useful for projects involving limited quantities of samples. In addition, the Core will coordinate collaboration with the Duke Stedman Nutrition Center to explore the utility of metabolomics for elucidating metabolic profiles in the high fat fed mice in Project 1. This information will be compared with the metabolomic profiles obtained from patients with knee OA participating in Project 3, funded through the Duke Aging Center. This novel and exciting approach will provide unique insights into the interactions of diet, obesity, and osteoarthritis. This Core will also serve as a resource for the training of investigators on principles and methods of biomarker analyses. We anticipate that this Core will stimulate collaborative interaction and facilitate the testing of central hypotheses related to this OA Program Project. Relevance to Public Health: This Biomarkers Core provides state-of-the-art analyses of joint tissue and inflammation markers. These markers, tested across all of the projects, provide a unique opportunity to understand the relationship of obesity and inflammation in osteoarthritis.